1899.] ON A ZOOLOGICAL EXPEDITION TO THE SOUTH SEAS. 7 



1. General Account of a Zoological Expedition to the South 

 Seas during the years 1894-1897. By Arthur Willey, 

 D.Sc. Lond., Hon. M.A. Cantab. 



[Received January 16, 1899.] 



The main object of my recent journey to the South-west 

 Pacific was the investigation of the life-history of tbe Pearly 

 Nautilus. My first destination was the Island of New Britain 

 (Neu-Pommern) in the Bismarck Archipelago, as this bad already 

 become known as a locality where living Nautiluses could beobtained 

 in abundance. The principal difficulties which had to be coped 

 with were owing to the comparatively deep water — 50 to 70 

 fathoms — in which Nautilus pompilius lives. It is only to be 

 caught at night — both in Blanche Bay and in Talili Bay, on 

 opposite sides of the Grazelle Peninsula — in native fish-traps baited 

 with small fish. After finding the tracts where Nautiluses congre- 

 gated in shoals at night, I would, on the following morning, go 

 over the same ground with the dredge. Almost always the dredge 

 would come up full of pumiceous fragments. In fact I came to 

 the conclusion in New Britain, which I afterwards confirmed in the 

 Loyalty Islands, that the feeding-ground is not the breeding-ground 

 of the Nautilus — or, in other words, that the Nautilus migrates in 

 shoals nocturnally from deeper into shallower water in quest of 

 food. The Nautilus wiU eat any auimal-food which is ofi^ered to 

 it, from a fowl to a sea-ui'chin, and from a langouste to a shrimp, 

 but its natural food consists chiefly of small Decapod Crustacea. 



When attacking a shrimp, for example, the Nautilus dart : 

 forward with great rapidity, and enclosing the victim within its 

 tentacular complex seizes it between its powerful beak-like jaws. 

 It can protrude its body by action of protractor muscles far beyond 

 the mouth of the shell, but it only does this when occasion demands. 

 When normally swimming, the body is slightly raised as to com- 

 pletely expose the eyes above the level of the margin of the shell, 

 and to allow free entrance for the water into the mantle-cavity 

 and exit through the cleft siphon. Like all the other Cephalopods, 

 Nautilus swims backwards with considerable speed. It holds the 

 shell, when swimming, in one position only, namely with the spire 

 and with the mouth of the shell directed upwards, as shovi'n in the 

 photograph here exhibited. Nautdus is incapable of capsizing its 

 boat as described b}'^ Bumphius. 



After spending the best part of a year in New Britain, during 

 which I made new observations upon the vascular system and 

 branchial sense-organs, I determined to change my base, and 

 accordingly proceeded to the Eastern Archipelago of British New 

 Guinea. Meanwhile, however, I had made a prospecting journey 

 to New Hanover, where I found the natives bahng out their canoes 

 with Nautilus -shells. I made no further progress during the five 

 months I spent in New Guinea so far as Nautilus is concerned. 



